modal verb

must

Translation

must, have to, an essential thing

You must finish your homework.

He must be tired.

This new phone is a must-have.

must + [base form of verb] to have to do sth. You must stop at the red light.

must be + [adjective/noun] to be certainly sth. She isn't answering her phone, she must be busy.

a must [noun] an essential thing This book is a must for all students.

Synonyms: have to, need to, should

From Old English 'moste', past tense of 'motan' meaning 'to be allowed, have to'.

Think 'I MUST do this, it's a MUST!' to remember both the verb and noun usage.